Circuit interrupting device



y 1941- T. LINDSTROM 2,240,623

CIRCUIT INTERRUPTING DEVICE Filed Oct. 26, 1959 2 Sheets-Sheet 2 j z'a. 4.

Non Magnetic Cofldllctigp Material Magnezz'a Wafer-in! u/azz'rz; Material Magnetic Material 36 INVENTOR be so constructed as to Patented May 6, 1941 &

2,240,623 CIRCUIT 1N TERRUP'I'ING DEVICE Ture Lindstrom, Edgewood, Pa.,

assignor to Westinghouse Electric & Manufacturing Company,

a corporation oi Pennsyl-' East Pittsburgh, Pa.,

Application October 26, 1939, Serial No. 301,422

34 Claims.

My invention relates generally to electric circuit interrupting devices, and more particularly to means for extinguishing electric arcs formed by such devices when operated to open an electric circuit.

De-ionizing plate structures for extinguishing electric arcs such as are shown in the patent to Jerome Sandin No. 2,160,681 usually comprise spaced plates positioned adjacent the path along which an arc is to be drawn substantially perpendicularly thereto, and are provided with some electrical or magnetic means, for causing the arc to be moved into the plate structure to break up the arc, cool the same, and de-ionize the arc path to extinguish the ar The plate structure may I cause such a movement of an arc, and it may further move the are into a slot having converging walls, to construct the arc prior to breaking up the arc to aid in extinguishing the arc.

In such prior devices depending upon movement of the arc into an arc extinguishing structure, movement of the arc may be erratic and obviously depends upon the amount of current in the arc, and hence the movement of the arc and the effectiveness of the arc extinguishing structure varies with arcs of diflerent current values. 7 g

It is an object of myinvention, therefore, to provide an arc extinguishing structure which will operate with equal efiectiveness to extinguish arcs of any current magnitude.

It is a further object of my invention to provide arc extinguishing plate structure which is movable into the arc to be extinguished.

It is a further object of my invention to provide arc extinguishing plate structure which is movable into the arc path by means independent of the arc.

Another object of my invention is to provide an arc extinguishing structure which effects a mechanical pinching or slicing of the are into a plurality of serially arranged arcs.

Still another object of my invention is to provide an arc extinguishing structure which is movable in response to the striking of an arc to extinguish the same, and is provided with means to restore the structure to normal position following the extinction of the arc.

Another object of my invention is to provide a novel form of arc extinguishing plate structure.

Another object of my invention is to provide arc extinguishing plate structure which is givenan impact to move the same into the path of an electric arc.

Stil1 another object of my invention is to provide in a circuit breaker, novel means for absorbing the shock of opening movement of the breaker.

These and other objects of my invention will become more apparentupon consideration of the following specification of preferred embodiments thereof, taken in connection with the attached drawings, in which:

Figure 1 is a longitudinal cross-sectional view showing a circuit breaker embodying my invention;

Fig. 2 is an enlarged plan view of the are extinguishing assembly shown in Fig. l, with the moving contact shown in cross section;

Fig. 3 is a side view of the assembly shown in Fig. 2;

Fig. 4 is a plan view of a plate used in the assembly shown in Figs. 2 and 3;

Fig. 5 is an edge view of the plate shown in Fig. 4

Fig. 6 is an enlarged cross-sectional view through the arc extinguishing assembly substantially on the line VI-VI of Fig. 2, but showing a. slightly different form of plate structure;

Fig. 7 is a plan view of the plate used in the assembly shown in Fig. 6; and

Fig. 8 is a 'plan view, showing a movable-contact in cross-section, of'a modified form of arc extinguishing assembly.

Referring to the drawings,- in Fig. 1 I have shown a circuit breaker which includes a housing 2 of insulating material, such, for example, asa molded insulating material such as Bakelite or the like. The circuit through the circuit breaker shown in Fig. 1 extends from one terminal 4 of the breaker by a conductor 5 to one leg of an inverted, substantially U-shaped bimetallic member 6, through the bimetallic member and from the other leg thereof to a flexible conductor 8, which is connected with a movable contact carrying arm in which carries at its outer end a laterally extending contact portion II. The contact carrying arm In and contact portion II are preferably formed of any suitable conducting material such, for example, as copper or the like and the contact portion ll preferably has at its outer end a portion of speciab arcing metal, such, for example, as a tungsten or silver alloy.

The contact portion H, in the position of the breaker shown in Fig. l, is in engagement with an insert l5 provided in the bottom plate l2 of an arc extinguishing assembly It. The insert I 5 is also preferably formed of a special arcing metal and may be of the same material as the arcing tip of the contact portion H. A conductor l4 connects the bottom plate I2 of the arc extinguishing assembly l3 with the other terminal I6 of the circuit breaker.

The movable contact carrying arm II! is fixedly secured to .a link l3 which has one end thereof plvotally mounted on a pivot pin 20 supported on a substantially U-shaped support 22 rigidly mounted in the circuit breaker casing 2. The other end of the link I8 is plvotally connected, as by the pivot pin 24, with a toggle link 26 which, in turn, is pivotally connected, as by the pivot pin 23, with another toggle link 33 which is pivotally supported by the pivot pin 32 on an upper toggle support member 34.

A circuit breaker operating member 36 is pivotally supported on the U-shaped support 22 by the pivot pin 33, and includes an outer arcuate portion 40 of insulating material which may be of the same material comprising the housing 2, which arcuate portion underlies an opening 42 in the outer side of the circuit breaker housing. Thecircuit breaker operating member terminates in an operating portion 44 which projects through the opening 42 for manual operation of the breaker. A coil tension spring 46 is connected at one end to an apertured tab 43 integral with the upper end of the circuit breaker operating member 36, and has its other end hooked over the toggle pivot pin 28.

In the operation of the circuit breaker thus far described, assuming the parts to be in the position shown in Fig. 1, wherein the circuit through the breaker is closed as described above, when the operating member 36 is moved by its knob 44 in a counterclockwise direction from that shown in Fig. 1, it is obvious that at substantially the midpoint of its movement between the ends of the housing slot 42, the upper end of the spring 46 will be moved by the operating member past a line through the toggle pivots to exert a force on the toggle pivot pin 26 to the left of the toggle as viewed in Fig. 1, to thereby break the toggle and move the contact arm carrying link l8 and therefore the contact carrying arm in and contact portion I l upwardly about the pivot pin 26 as an axis, with a snapaction to open the circuit through the circuit breaker. It is obvious that movement of the circuit breaker operating member in the opposite or clockwise direction will 01)- erate the parts in a reverse manner. In' other words, movement of the circuit breakenoperating membenin a clockwise direction when the breaker is open will move the upper end of the spring 46 to the right of the toggle as viewed in means will be hereinafter referred to more in detail.

The upper toggle supporting member 34, as shown in Fig. 1, is substantially L-shaped in form and the short leg thereof is pivotally mounted on the U-shaped supporting member 22 as by the pivot pin 50, and the outer end of the long leg of the upper toggle supporting member 34 carries a projecting insulated catch member 52 which normally engages beneath a stop member 54 secured to the upper end of the bimetallic member 6. The operating member 36 of the circuit breaker is further provided with a laterally extending stop portion 66 for engagement with the upper toggle supporting 'member 34.

Since the bimetallic member 6 is in series through the circuit breaker member, it is obvious that upon the occurrence of a predetermined overload in the circuit with which the breaker is associated, the bimetallic member 6 will be deflected to the left as viewed in Fig. 1, to disengage the toggle support 34, thus rotating, under the influence of spring 46, the toggle pivot 32 to a position to the right of the line of action of spring 46, thereby causing this spring to break the toggle and move the contact carrying arm l0 and contact portion l I out of engagement with the bottom plate l2 of the arc extinguishing assembly 13 to interrupt the circuit through the breaker.

A laterally extending stop portion 63 is provided integrally with the U-shaped supporting member 22 for engagement with a notch 6| in the Fig. 1, and thereby tend to straighten the toggle and move the links thereof to the position. illustrated in Fig. 1 with a snap action. This snap action movement of the contact carrying arm l3 and contact portion l l is desirable to obtain rapid attenuation of the are formed when the breaker is opened, and to obtain rapid and positive engagement of the contact portion H with the bottom plate l2 of the arc extinguishing assembly when the breaker is closed.

In the opening movement of the circuit breaker the contact carrying arm HI and its associated parts, when moved with a snap action, have considerable inertia which has to be absorbed. I have provided means integral with the are extinguishing assembly l3 for at least in part absorbing the shock of decelerating the opening movement of the contact carrying arm in which upper toggle supporting member 34 to limit the movement of the supporting member 34 when it is released by the bimetallic member 6. The upper toggle supporting member 34 may be reset by moving the circuit breaker operating member 36 in a counterclockwise direction as viewed in Fig. l to engage the stop 56 with the upper toggle support 34 and move the same in a counterclockwise direction about its pivot 56 to engage its catch portion 62 beneath the bimetallic stop 54.

It should thus be apparent from the foregoing that my invention is embodied in a circuit breaker permitting a manual opening and closing movement of the circuit through the breaker as well as providing for an automatic opening of the circuit through the breaker upon the passage of currents therethrough above a predetermined value. Furthermore, it should be noted that all of these movements are accomplished with a quick, or a snap action of a movable contact.

The are extinguishing assembly I3 is shown more in detail in Figs. 2, 3 and 4. As shown in these figures, the assembly includes a top terminal plate 58 secured in spaced relation to the bottom assembly plate I2, by the insulating spacer members 62, which are secured to the plates by any suitable means such, for example, as by the machine screws 64 passing through apertures in the plates to threadedly engage suitable fittings provided in the outer ends of the insulating spacer members 62. There are four of these spacer members, as is apparent from Fig, 2.

Two sets of de-ionizing plates are pivotally supported between the terminal plates 58 and I2 on an insulated pivot pin 66. The plates 63 and III, which are identical in shape are more particularly shown in Fig. 4 to include an aperture 82 for the reception of the pivot pin 66, and a side aperture 60 for the reception of the tie pins 12 or 14. The plates also further include an elongated aperture fll through which the contact portion i i is adapted to extend. The plates 63 are tied together and maintained in spaced relation from each other and from the terminal plates I2 and 58 by the insulated tie pin I2. These plates are also insulated from each other and from the pin and top and bottom terminal plates I2 and 58. As before stated, the plates 68 and I are identical in form and may be used interchangeably, the only difference in the assembly of the device being that the plates 68 are assembled in opposition to, or facing the plates I0. The plates I0 are tied together by a tie pin I4 and are maintained in spaced relation with respect to each other and to the top and bottom terminal plates I2 and 58, and are located in staggered relation with respect to the plates 68 so that they may enter in the spaces between the plates 68 in an interleaved relation. As shown in Figs. 2 and 3, the outer end spacing members 62 are of enlarged rectangular shape in cross section, and are provided with spaced slots 65 for guiding the outer ends of plates 68 and I0, and with offset flanges 63 projecting from opposite ends of each of the outer spacing members 62 to closely engage an edge of the terminal plates I2 and 58 for preventing relative rotation of these parts. 7

The plates further include extended ear portions 84 having an aperture at the free end thereof for receiving an insulated pin 90 to which are hooked the ends of coil tension springs 92 to maintain the plates 68 and I0 substantially in the position shown in Fig. 2.

The springs 92 are preferably made just strong enough to maintain the plates in the positions shown in Fig. 2 when the circuit through the circuit breaker has been interrupted. Additional means are provided for locking the plates in this position, and for limiting their outward movement, and in the embodiment shown comprise toggle links 93 and 94 connected at adjacent ends by a toggle pivot pin 96 and having their opposite tures inlinks 93 and 94, respectively, for normally a urging the adjacent ends of the toggle links in a direction toward the contact portion II, or to the left as viewed in Fig. 2. The spring 98 need not be very strong inasmuch as it is'not depended upon to maintain the plates 68 and I0 in the position shown, this function being allotted to the coil tension spring 92. The sole function of the to gle spring 98 is to straighten the toggle when it is at, or substantially at its dead center position, which will require but little force.

The toggle spring 98, as stated before, is adapted to move the toggle pivot 96 toward the contact portion II. This movement of the toggle is stopped by an impact member I02 having a portion extending alongside the toggle links substantially at the toggle pivot 96, and which is pivotally mounted as at I00 on the top terminal plate 58 of the arc extinguishing assembly I3. The impact member I02, as viewed in Fig. 3, is offset from its pivot I00 and its movement in a counterclockwise direction is limited by engagement of its offset portion with the top terminal plate 58. This in turn limits movement of the toggle links 93 and 94 in a direction toward the contact portion I I. The parts are preferably conthe toggle to its dead center position, or slightly beyond its dead center position towards the contact portion II. As shown in Fig. 3, the contact carrying arm I0 is electrically connected with the top terminal plate 58 of the arc extinguishing assembly I3 by a flexible conductor 60 for a purpose to be hereinafter referred to.

The de-ionizing plates 68 and I0 are preferably of a composite structure, and, as shown in Fig. 4, include a substantially L-shaped main portion I6 which is formed of any desired magnetic material such, for example, as soft iron, to which is secured an insert II of non-magnetic material which may be any desired non-magnetic material and in this form of my invention is preferably of a good heat conducting material such, for example, as copper or the like. The insert is secured'to the magnetic portion I5 by spaced stamped portions I9 and by interlocking shoulder portions BI and 83.

In the operation of the arc extinguishing assembly thus far described, it is obvious that when the contact portion II is moved upwardly as viewed in Fig. 3 to open the circuit through the breaker, that an arc will be established between the end of the contact portion II and the contact insert I5. The are thus established will set up magnetic forces through the magnetic portions I6 of the de-ionizing plates, which forces will tend to move the plates together. The strength of the coil springs 92 maintaining the plates in the relatively separated position shown in Fig. 2 is such that it will be overcome by the magnetic forces exerted between the plates; the plates are, however, locked in the position shown in Fig. 2 by the toggle until, as the contact portion I I rises out of the apertures through the deionizing plates, an integral projection I04 thereon engages the impact member I02 with an impact, to rotate the impact member in a clockwise direction aboutits pivot I00 to thereby break the toggle links 93 and 94, and release the plate members so that they may move towards each other with the tie pins 12 and I4 moving through slots I3 and I5, respectively, provided in the upper terminal plate 58. This movement of the impact member I02, in addition to releasing the toggle lock which maintains the plates in the separated position shown in Fig. 2, will also-be operative to move the toggle pivot 96 a substantial distance to the right of that shown in Fig. 2, and therefore move the plates a substantialdistance together thus giving an initial impetus or additive force to the magnetic forces generated by the arc and tending to move the plates together. The contact portion I I may then move completely out of and away from the arc extinguishing assembly I3 and the flexible shunt 60 is provided to the top terminal plate 58 of the assembly to transfer the arc to the top plate in the event that it has not been extinguished by the time the contact portion-moves away from the arc extinguishing assembly.

As the de-ionizing plates move together from the position shown in Figs. 2 and 3, they exert a scissors-like action on the are formed to break up the are into a series of serially arranged arcs between the plate inserts II, which are then extinguished by the de-ionizing action of the plates, which is now well known in the art. I have found that the magnetic forces set up in the soft iron of the de-ionizing plates which tends to move the plates together or tends to cause relative movement of the plates and are, is exerted substantially from a point midway between the edges of the soft-iron plate on a line drawn from the arc outwardly. Therefore, to obtain maximum movement of the are into the plate structure and at the same time relieve the magnetic material from the deleterious effects of arcing, the insert 11 of non-magnetic material is provided, thereby moving the point from which the magnetic force is exerted on the arc to a position lying midway between the sides of the magnetic member 16. It is obvious that this will cause greater relative movement of the arc and de-ionizing plates than if the plates were entirely of magnetic material, in which event the point at which the magnetic force is exerted would lie substantially midway between the edges of the plate as a whole and thearcing aperture 18. Also, the arc will be confined to the insert 11. As stated before, the insert I1 may be of any desired non-magnetic material. In this form of my invention I preferably use inserts which are of good heat conducting ability to aid in cooling the arc and hence to aid in its extinction. It should be noted here that the impact member I02 not only acts to initially release the toggle lock maintaining the deionizing plates in the positions shown in Fig. 2, but mechanically gives these plates an initial impetus or movement to ards each other, and because of this work performed by the impact member, it also serves as a shock absorbing medium for the moving contact carrying arm l and contact portion II to absorb a. great part of the kinetic energy of these moving parts and thus lessen the shock on the operating mechanism of the circuit breaker.

After the circuit has been interrupted by the de-lonizing action of the plates 68 and 10, ohviously the magnetic forces tending to draw the plates together will disappear and the coil springs 92 are then effective to separate the plates and move them to the position shown in Fig. 2. As stated before, these springs 92 are relatively weak and are just strong enough preferably, to restore the plates to their initial position when the circuit through the breaker is open and hence no magnetic forces are acting in opposition to the spring. However, the springs 32 of such a construction would be unable to reset the toggle links 33 and 94 attheir dead center position or beyond it inasmuch as a relatively great force would have to be exerted by the springs 92 to finally straighten these toggle links. However, only a relatively small force need be exerted at the toggle pivot 96 on the toggle links. Movement of these links to their final dead center position or even slightly beyond the same is the function of the small coil spring 98. Thus after the circuit has been interrupted, the plates are automatically reset in the position shown in Fig. 2 with the holes 18 in alignment to again receive the contact portion I I, and are also automatically relocked in this position by the spring toggle mechanism 53 and 94.

In Figs. 6 and '7 of the drawings, I have shown sleeve I08 interposed between the bolt and the plate apertures. Also an insulating washer III and a lock washer II3 are provided between the head of the bolt IIS and the adjacent end of the insulating sleeve I08. Insulating spacer members I I0 are provided between the plates and between the head of the bolt and the adjacent plate, and an elongated spacing plate I I8 is provided between the upper plate and .an insulating washer I20 positioned beneath a nut I22, which is engageable with a threaded portion adjacent the end of the bolt. Another insulating washer I24 is positioned between the nut I22 and toggle link 93 as is apparent from Fig. 6. The insulating sleeve I08 and the insulating spacer sleeves, as well as the insulating washer members may be of any suitable insulating material such, for example, as fibre, or a molded insulation material.

As in the previously described embodiment of my invention, two sets of de-ionizing plates are provided between the assembly terminal plates I2 and 58. One set of plates I28 being tied together by the tie pin 12, is identical with the plates previously described in connection with the embodiment of the invention shown in Figs. 1 to 4. In other words, the plates include substantially L shaped magnetic portions with copper inserts to help to cool the are formed by interruption o! the circuit through the breaker. The other set of plates I30, however, has inserts of insulating material I34 in the L-shaped magnetic portions I32 to provide, when the plates are moved together, alternate plates of insulating material I34 and good heat conducting material for the serially arranged arcs. It should .be understood that many other arrangements of plates having inserts of insulating and heat conducting material may be made other than that specifically shown in Fig. 6, also all of the plates may have inserts of insulating materiaL'ii desired. It has been found that the combinations of plates having different inserts are highly desirable in de-ionizing plate are extinguishing structures, it being essential only that the inserts be of a non-magnetic material.

The insulating inserts I34 may be of any desired insulating material such as fibre, asbestos, or a molded insulating material. If made oi! fibre, obviously when contacted by an arc, quantities of unionized gas will be evolved to further aid in extinguishing the arcs. Thus in this structure not only the well known deionizing action of plates isutilized to extinguish electric arcs, but also a cooling action caused by the inserts of heat conducting material is utilized to cool down the arc, and insulation is interposed in the arc and unionized gas may or may not be evolved to further aid in extinguishing the arc. All of these different actions give rise to a peculiarly eflicient arc extinguishing action.

Both sets of plates I28 and I30 in this form of my invention may be provided adjacent their inner edges on opposite sides thereof, with in-- sulating baiiie members I26 as clearly appears in Figs. 6 and 7. As shown in Fig. 7, these baiiies are slightly arcuate in form to present a concave side to the aperture 13 through which an arc is drawn. The function of these baflles I25 is to aid in moving the plates I28 and I30 together.

This is accomplished by the reaction force of the arc gases against the bailles I26 which, as is clearly apparent from Fig. 6, will be in a direction to move the plates further together to a more complete interleaved relation.

The plates I 28 and I30 in this embodiment of my invention are also provided with an insulating strip I36 extending entirely about the outer periphery of the plate as well as about the edges of all the apertures through the plate. This insulation provided about all the edges of the plates is designed to prevent movement of the are beyond the boundaries of the plates.

The operation of this embodiment of my invention is substantially identical with that of the previously described embodiment and hence will not be repeated in detail here. The plates are moved apart and together in the same manner as the plates 58 and III in the previously described embodiment of my invention. However, it should be noted that an additional force is available in this embodiment of my invention for moving the plates together, namely, the reaction force of the arc gases acting against the insulating baffle members I26 integral with the plates. Thus, in this embodiment of my invention, there are, in effect, three distinct forces tending to move the plates together to slice the arc into a series of smaller arcs, namely, the magnetic force due to the presence of the magnetic portion of the deionizing plates adjacent to the arc path, a mechanical impact force delivered by the lug I04 on the contact portion II for initially giving an impetus to the plates to move them together a substantial distance, and thirdly, the force due to the arc gasesacting against the insulating baflles I26 on the plates.

In Fig. 8 I have illustrated a simplified form of deionizing plate structure which merely includes plates I 38 and Ill pivotally mounted on a pivot pin I46 with an insulating sleeve I48 between the pin and plates. These plates are not apertured to receive the movable contact I42, but are provided with inserts I44 which may be of insulation material, or heat conducting material, or both, as desired. Normally, the plates lie in the position shown in Fig. 8 with end portions thereof spaced to provide an arc passage through which the movable contact member I42, shown in cross section, may be moved to drawan arc. Ob-

viously when an arc is drawn between the free ends of the plates "by the movable contact I42, magnetic forces set up in the magnetic portions of the plate will cause the plates to approach each other to move through the arc with a slicing or scissors-like action and extinguish the are by the deionizing action of the plates. This is an extremely simplified form of movable de-ionizing plate structure and has been illustrated without any means for resetting the plates following a circuit interruption.

It should be apparent from the foregoing that I have provided a novel arc-extinguishing structure for use in a circuit interrupting device which includes a plurality of deionizing plates which are movable in response tothe striking of an electric are, through the arc to cut or slice the are into a plurality of serially arranged arcs to. deionize the arc stream and thusextinguish the are. It should also be apparent that I have disclosed novel deionizing plate structures especially adapted to insure a maximum of relative movement between the arc and the plates to bring the arc well into the plate structure, and wherein means are incorporated in the plates for cooling the are, for

. opening movement.

anism for acting as a shock absorbing means for the moving contact of the breaker, at least in its Although I have disclosed my invention in connection with a particular circuit breaker operating mechanism wherein it has certain novel features of cooperation, it is obvious that it is not limited for use solely with the mechanism disclosed, but may be employed with the separable contacts of circuit interrupters having other types of operating mechanism. The particular operating mechanism herein disclosed is of the general type disclosed and claimed in the patent to F. G. Von Hoorn, No. 1,786,796, issued December 30, 1930, to the assignee of this invention.

Having described preferred embodiments of my invention in accordance with the patent statutes, I wish it to be understood that I do not wish to be limited to the particular embodiments disclosed herein inasmuch as it will be obvious, particularly to persons skilled in the art, that many 1. In a circuit interrupting device, means for drawing an are along a predetermined path, an arc extinguishing structure including spaced plates mounted for movement into and out of the path of the arc and magnetic means for moving said plates into said are path independently of the speed at which said arc is drawn.

2. In a circuit interrupting device, means for drawing an arc along a predetermined path, an arc extinguishing structure mounted for-movement into and out of the path of the are, and means operated by the are for moving said structure into the path of said are independently of the speed at which said are is drawn.

3. In a circuit interrupting device, means for drawing an arc along a predetermined path, and an arc extinguishing structure including spaced plates at least partially of magnetic material freely mounted for movement into and out of the path of the arc.

4. In a circuit interrupting device, means for drawing an arc along a predetermined path, and an arc extinguishing structure including spaced apertured plates mounted for movement into and out of the path of the are, said plates normally positioned with their apertures aligned along said are path, and means for moving said plates to move the apertures thereof out of said path and to move solid portions of said plates into said are path in response to the striking of an are along said path.

5. In a circuit interrupting device, means for drawing an are along a predetermined path, and an arc extinguishing structure including spaced plates mounted for movement into and out of the path of the are, means for moving said plates into said are path in response to the striking of an are along said path, and means for resetting said plates in response to the extinction of said are. e

6. In a circuit interrupting device, means for drawing an are along a predetermined path, and an arc extinguishing structure including spaced plates mounted ior movement into and out oi? the path of the arc, toggle means for locking said plates in a position outside said are path, and means associated with said are drawing means for tripping said toggle means in response to the drawing of an arc.

'7. In a circuit interrupting device, means for drawing an are along a predetermined path, an arc extinguishing structure including spaced plates mounted for movement into and out o! the path of the arc, and means associated with said plates and positioned to be acted upon by the arc gases in a manner to move said plates into the path of said arc.

8. In a circuit interrupting device, means tor drawing an are along a predetermined path, an arc extinguishing structure including sets oi. spaced plates mounted for movement into and out of interleaved relation in said are path, resilient means normally maintaining said sets of plates in at least a partially separated position, means tor locking said plates in the latter position, and means responsive to the striking of an are for releasing said locking means and moving said plates to said interleaved position.

9. In a circuit interrupting device, means for drawing an arc along a predetermined path, and an arc extinguishing structure including sets of spaced plates with the plates of each set secured for movement together at a plurality of spaced points and pivotally mounted for movement into and out o! interleaved relation in said are path at a point spaced from said points or securement.

10. In a circuit interrupting device, means for drawing an are along a predetermined path, an arc extinguishing structure including sets of spaced plates with the plates or each set secured for movement, together and pivotally mounted about a common axis for movement into and out of interleaved relation in said are path, locking means cooperable with said plates, and biasing means for normally maintaining said plates in a predetermined position,

11. In a circuit interrupting device, means for drawing an are along a predetermined path, and an arc extinguishing structure including sets of spaced plates mounted for movement into and out oi! interleaved relation in said arc path, and insulating means secured about the periphery of each or said plates.

12. In an arc extinguishing device, a pair of imulated spaced apertured terminal plates of conducting material, and a plurality or spaced arc extinguishing plates movably supported between said terminal plates and insulated therefrom and from each other.

13. In a circuit interrupting device, a pair insulated spaced terminal plates, a plurality of spaced are extinguishing plates supported between. said terminal plates movably and insulated therefrom and from each other, an aperture through each of said are extinguishing plates and one of said terminal plates, and a movable contactmember movable through said apertures to engage said other terminal plate, and being electrically connected with said one terminal plate.

14. In a circuit interrupting device, means for drawing an arc along a predetermined path, an arc extinguishing structure including sets of spaced plates with the plates of each set secured for movement together and pivotally mounted for movement into and out of interleaved relation in said are path, resilient means normally maintaining said sets of plates in at least a partially separated position, and means associated with said arc drawing member for moving said plates toward said interleaved position.

15. In a circuit interrupting device, means for drawing an arc along a predetermined path, an arc extinguishing structure including sets oi! spaced plates with the plates of each set secured for movement together and pivotal-1y mounted for movement into and out of interleaved relation in said are path, mean-s normally locking said sets of plates in an inactive position, and means associated with said are drawing means for releasing said locking means when an arc is drawn.

16. In a circuit interrupting device, means for drawing an are along a predetermined path, an arc extinguishing structure including sets of spaced plates with the plates of each set secured for movement together and pivotally mounted for movement into and out of interleaved relation in said are path, means normally maintaining said sets of plates in at least a partially separated position including toggle means associated with said sets of plates and resiliently urged to a deadcenter position, and means associated with said arc drawing member for breaking said toggle means to move said plates to said interleaved position.

17. In a circuit interrupter, a contact movable into and out-of engagement with a cooperating contact, snap action means for moving said movable contact out of engagement with said cooperating contact, are extinguishing plate means movable into and out of an arc extinguishing position with respect to said contacts, and means associated with said plate means and positioned to be engaged by said movable contact to move said plate means into said are extinguishing position with an impact, in response .to a predetermined movement of said movable contact out oi! engagement with its cooperating contact.

18. In a circuit interrupting device, means for drawing an are along a predetermined path, and

an arc extinguishing structure including sets of spaced plates with the plates of each set secured for movement together and positioned to telescopically enter the spaces between the plates of the other set when the plates are moved together, aligned apertures through the plates of each set, with the apertures in one set of plates adapted to register with .the apertures through the other set of plates in one telescoping position or said sets of plates to form an opening through which said are drawing member is movable to draw an arc, said plates being movable to another telescoping position when an arc is drawn in said opening to bring said plate apertures out of alignment.

19. In a circuit interrupting device, a pair of insulated spaced terminal plates, sets of spaced arc-extinguishing plates movably supported between said terminal plates with the plates of each set being adapted to move to a plurality oi. telescoping positions with respect to the plates of the other set, apertures through said arc-extinguishing plates and one of said terminal plates adapted to be aligned in one telescoping position of said plates to form an arc passage, and a movable contact electrically connected to said one terminal plate and movable through said passage to movable plates of a magnetic material, with the portion of each plate, adjacent said arcing path being of a material capable of evolving an arc extinguishing gas when in proximity to an electric arc.

21. In a circuit interrupting device, means for drawing an are along a predetermined path, and an arc extinguishing structure including spaced plates mounted for movement into and out of the path of the arc, and each plate including insulating means securing about the edges thereof.

22. In a circuit interrupting device, means for drawing an arc along a predetermined path, and

an arc extinguishing structure including spaced plates at least partially of magnetic material mounted for movement'into and out of said are path, and at least the portions of said plates movable into said path being of a material which is capable of evolving an arc extinguishing gas when in proximity to an electric arc.

23. In a circuit interrupting device, means for drawing an are along a predetermined path, and an arc extinguishing structure including spaced apertured plates mounted for movement into and out of the path of the arc, said plates normally positioned with their apertures aligned along said arc path, and means for moving said plates to move the apertures thereof outof said path and to move solid portions of said plates into said arc path in response to the striking of an arc along said path, and means of insulating material forming at least edge portions of said plates.

24. In a circuit interrupting device, means for drawing an are along a predetermined path, and an arc extinguishing structure including spaced apertured plates mounted for movement intoand out of the path of the are, said plates normally positioned with their apertures aligned along said arc path, and means for moving said plates to move the apertures thereof out of said path and to move solid portions of said plates into said are path in response to the striking ofan arc along said'path, and bailie means associated with at least some 01' said plates at one side or the aperture in the respective plates, so that gases generated by said are will act to move said plates.

25. In a circuit interrupting device, means for drawing an are along a predetermined path, and

an arc extinguishing structure including spacedplates mounted for movement into and out of the path of the are, means for moving said plates into said are path in response to the striking of an are along said path, and resilient means for maintaining said plates outside of said are path in the absence of an arc.

26. In a circuit interrupting device, means for drawing an arc along'a predetermined path, and an arc extinguishing structure including spaced plates mounted for movement into and out of the path of the are, means for locking said plates in a position outside said arc path, and means responsive to the striklng of an are along said path for releasing said locking means and moving said plates into said arc path.

27. In a circuit interrupting device, means for drawing an arc along a predetermined path, and an arc extinguishing structure including spaced plates mounted for movement into and out of the path of the are, means for locking said plates in a position outside said are path, means responsive to the striking of an are along said path for releasing said locking means and moving said plates into said are path, and resilient means for maintaining said plates in a position outside said arc path in the absence of an arc, whereby said plates are automatically locked in the latter position in response to extinction of an arc.

28. A plate for an arc extinguishing plate structure having an aperture through which an arc is adapted to be drawn, and bailie means at one side of said aperture so as to be acted upon by the arc gases to exert a bias on said plate.

29. In an arc extinguishing device, a pair of insulated spaced terminal plates ofconducting material, and a. plurality of spaced arc extinguishing plates supported between said terminal plates and insulated therefrom and from each other, said are extinguishing plates being movable relative to said terminal plates, and means cooperating solely with said plates to limit relative movement thereof in opposite direction.

- 30. In a circuit interrupting device, means for drawing an are along a predetermined path, an arc extinguishing structure including sets of spaced plates with the plates of each set secured I for movement together and pivotally mounted for movement into and out of interleaved relation insaid arc path, means normally maintaining said sets of plates in at least a partially separated position including toggle means associated with said sets of plates and resiliently urged to a dead-center position, and means associated with said are drawing member for engaging said toggle means with an impact after predetermined movement of said are drawing member from its closed circuit position, to break said toggle means and move said plates to said interleaved position.

31. In a circuit interrupting device, means for drawing an arc along a predetermined path, an arc extinguishing structure mounted for movement into and out of the path of the are, means operated by the are for moving said structure into the path of said are independently of the speed at which said arc is drawn, locking means for maintaining said structure out of said are path, and means engageable by said are drawing means only after predetermined movement thereof along said path to draw an arc to release said locking means, whereby the energy of said are utilized to niove said structure is suddenly released after an arc is established so that said structure is moved substantially with v a snap action into said path.

32. In a circuit interrupting device, means for drawing an arc along a predetermined path, and

an arc extinguishing structure including spaced 4 plates of a magnetic material, with the portion of some of said plates adjacent said are path being of a material capable of evolving an'arc extinguishing gas when in proximity to an electric arc, and the portions of others 01' said plates adjacent said are path being of conductive mate- 33. In a circuit interrupting device, means for drawing an arc along a predetermined path, and an arc extinguishing structure including spaced plates of a magnetic material, with the portions of alternate plates adjacent said are path being of a conducting material and a material capable of evolving an arc extinguishing gas when in proximity to an electric arc, respectively.

34. In acircuit interrupter, a contact movable into and out of engagement with a. cooperating contact, snap acting operating mechanism for moving said movable contact into and out of engagement with said cooperating contact, arc

extinguishing means movable into and out of an contact, for at least initiating movement of said are extinguishing position with respect to an are are extinguishing means to said arc extinguishdrawn between said contacts, and including ing position, and thereby to at least retard means adapted to be actuated by said movable further movement of said movable contact in contact only after predetermined movement 5 the same direction.

thereof in a direction away from said cooperating 'I'URE LINDSTROM. 

